Railway truck structure



Jan. 29, 1946. J, c, TRAVILLA, JR v 2,393,722

RAILWAY TRUCK STRUCTUR Filed Jan.4 28, 1944 vll/4 I JAMES C.*TRAV|'1LAIJR.

' ATTORNEY Patented Jan. 29, 1946 3,393,722 nAnlwAY TRUCK surnuc'rnnaJames C. Travilla,` Jr., Swarthmormlaw assignor to. GeneralL SteelCastings Corporation, Granite (3 iIty, ,Illv.,l a corporation ofiyDelaware Application .nnary 2s, israserial No, s-zoioor.4

4 claims.- (ormai-'195),

The invention relates to railway rollingstock and' consists irr ay truckstructure and more` parti'cularly in the spring support of the trucktrame.

The main object of the inventionx is toprovide for easyv spring actionwhen the vehicle is unloaded or is lightly loaded and to provideincreased spring capacity under aheavier load or under greater springlcompression. This object is'- attained by associating a spring sn-ubberVwith aportion of the spring structure andl providing fortlie'functioningof the snubbe-r duringh a portion only of the springaction.

Anotheri object is to group a' free acting spring and' a spring whichissnubbed', atV least; during a portion of 'its movente-nt, so thattheir combined actionwillv be` bestadapted' f orthe dis:- tribution oftheir load to their support'. More particularly it is desired to disposea` free acting spring and a spring which is snubbed,` at least during aportion of its movement, along an equalizer bar extendingn between truckaxles so asto effectively prevent bouncing of the Vehicle withoutsnubbing the equalizer movement. This feature is particularlydesirable., in a six-wheel truck in which the load applied to one springgroup is distributed unequally to the adjacent axles andthe object isattained by positioning the free acting spring nearer thev aXle whichreceives the greater portion of they load' and positioning the snubbedspring nearer to the other axle.

These, and ,otherl detail objects are attained by the structureyillustrated inthe accompanying drawing, in which-f- Figurer 1. is a sideelevation of a.. six-wheel truck and shows thegeneral arrangement of thesprings and associated parts.

Figure 2 is a vertical sectionxthrough one of the groups of springs,vshown inFigure. l, and the associated, parts, the` sectionV extendinglon,- gitudinally ofthe truck and being drawn. to an enlarged scale. Thegroup includes a.. free acting spring and a spring provided, with asnubber butv the,- parts are. shown in a. positionv in which the snubberis not functioning..

Figure 3 is asimilar section. showing the parts in the position assumedwhen the. springs, and particularly the, right hand; spring, have, beencompressed. to anA extent at which the snubber wouldl begin to functionupon further compression of' the springs. l e

'Ijhe truck includes three spaced axles l1, 2 and 3 .inc1udingwheels 4mountedthereon and carryingL journal' boxes 5,; 6 and 1:; Equalizers tandI 9 extend between adjacent journal boxes at'. the same side;oiitheztruck'. and each equalizer isprovidedwith a saddle.x lilv for agroupf of spring units Ill and; t2 upon which; theaV truck frame Wheelpiecex l3fismounted.. Preferably the Wheel piece ist. of inverteda U1section` and; housesv the spring units Ill: andr t2. Swing hangers: i6;are pivotally suspended from. the truck. frame: and support the double;bolster |253 provided with the usual center plate IG. upon: which` thevehicle body (not shown)v isV mounted; This. general arrangement is:vwel'li knownk in,4 the art. and the novel featuresreside in. the spring:arrangement detailed inv Figur-esi21and'. 3.

Springy unit Hi comprises a-.iseriesiof coil springs lili, I'8 andvtoffdifferentrod. diameters and diiferentA col diameters, the smallerspringsf being placed inside the largerv springs. as. is customaryinrailway truck springs. Spring unit t2 comprisesY acoill spring 2Ucorresponding tto spring lll, but insteadi of the inner coilspringsisland i9; there is provided: a friction` snubbing deviceincludingtelescopingparts 2l, 22?, 232 arranged oneabove the other;theintermediate part 22 constituting a; wedge'l between: parts:v 2i., Ahelical spring tends tothrust parts. 22v and 24 apart; A bolt 2'5limitssuch relative movement of the parts and determines the height ofi thesnubber when itis inactive. adapter'l forms an upward extension'-v ofypart 23 and` could be integrali therewithexcept for the desirability ofadjusting the effective heiglitof thesnubber by substitution ofadaptersfof different:depthu The over all` height of the' snubbermaybe; less thanthey distance between. the equalizer and frame andthesmibber will; notfunction' ati all times, as'explainedt below,r and a relatively. lightspring.l 21 is-y compressed between a seat. on the snubber and thetruck.frame and. holds.- the adapter to its seat on the snub'berf andthesnubber'on its seat to the equalizer;

The springs are; so; designed that whenthe vehicle body is: empty andstatior-iary, the springs will be;;expanded;,with their, height as shownin Figure=.2,yand the top of. adapter. 2Evspaced from thecpposing faceofthe atop wall oi wheel. piece I3,I in- Whichposition the snubberr doesnot function. rIhe height of. the springs under such conditions may betermed their normal light load height. In. other words, the springs arecarrying only thefweight of, the truck parts which. they support andthevehicle. body.

The.v springsv are so designed that when r they vehicle body is loadedtoits full capacity and, is stationary, tlie springs will be compressed;until their height is as shown in Figure' 3, in-'which normal full load"height.

The snubber'is so designedthat it. will not function until the springwith'whichit'is Vasso-V ciated is Vfurther compressed. Suchi furthercompression of the spring, and resulting reduction in its height,mayresult irrespective of the' vehicle load during operationofjthevehicle;v

rWhen the vehicle is travelling alongthetrack, the body roll,particularly when the vehicle .is

rounding a curve, and irregularities inthe trackV cause'verticalmovement of theV vehicle body and truck frame relative to the'vvheelsland axles,v

good riding qualities irrespective Vof the body load.

center of which is preferably one-third of the distance between axle Iand axle 2, and the free acting spring ,unt Il is positioned nearer toaxle l and the snubbed spring unitY l2 is positioned nearer'to axle2.The minimum movementl of the equalizer Awould be fapprxirnately midwaybetween axles l Vand 2` and the'snubbed spring unit is fairly close tothis point. When the snubber is functioning, both spring units areloaded substantially equally but the frictional resistance to theiraction is applied to the unit nearer 'the midpoint between their axlesthanV would be the case if'both spring units included snubbers.Accordingly, bouncing action of the frame thus applying shocl to thesprings and causing.

the-springsY to alternately compress and expand inY relation to theirnormal heights underY given loads, such as their full load height ortheir light load heights. When the vehicle is empty or is loaded lessthan its full capacity, itis desirable to permit the'springsto` actfreelyzto provide for smooth easy riding because theV shocks which causespring oscillations are notas great as when the vehicle is fully loaded.YFor this reason, it is Vnot desirable to snub the action of thespringsat their heights when the vehicle is empty and when it is loaded lessthan its full capacity'because such snubbing action at these heightswould tend Vto wear outthe snubber.

When the vehicle Yis fully loaded, however, it is desirable to ,snub theaction of the springs when they are being compressed a greater amountdue to increased shocks yapplied to them lbecause there is a greaterpossibility of synchronization of rail joint impacts with the naturalfrequency of the springs, the natural frequency of the spring varyinginversely as its'load is increased, and due to synchronization of suchimpacts and spring frequency, the rebounds of the springs would then bemuch greater than they would be when the vehicle is lightly loaded,likely causing severe bouncing action of the vehicle body and its load.V l

yBy having the snubberA active from the full loaded height of spring tothe solidheight, the spring capacity in that rangeis increased due to`the snubber spring thereby tending to prevent the springs from goingsolid, andwhen the height of the springs is between full load height andlight load height the snubber is not active, thus providing flexiblespring action.

When the springs have compressed suiiiciently to bring adapter 26 andthe top wall of wheel piece I3 into contact (i. e., when the springs arecompressed to full load height), the snubber begins to offer irictional.resistance to further compression of the springs, and particularly ofspring 2D, and the greater the compression the greater the resistance.VSimilarly, as a result of the spring compressing force beingabsorbedatleast partially by `the snubber, too rapid rebound is prevented as theparts return to their .normal position. When the wheelv piecev Aandequalizer have moved away from each other to Y the extent that thespring height is' greater than its full load height, the top of thewheel piece' and the adapter. are. separated from, each other andfurther spring expansion isunaiected by thesnubber.Y Accordingly, thesprings will' react in a mannerywhereby' the truck possesses asawhole isresisted while the pivotal action of theV equalizer about its center isnot unduly restricted.Y This positioning 0f the Vgroup of springsrelative tothe axles and the positioningV `of the snubber-associatedspring in .the spring group contributes to thegood ridingcharacteristics of the truck. Y i

embodiment of the invention illustrated, but -it is to be understoodthat'other arrangements Ymay embody different features of the invention.Other types of snubbers could be substituted for that shown. The featureofthe snubber operating approximately only during the movement of theframe-supporting spring between'its normal full load height and itssolid height may be provided in the other spring supporting the truckframe instead oir in the-spring nearer the middle axle. If desired,yeach supporting spring may have a snubber functioning in the specifiedmanner associated therewith, or the frame might be supported by a singlespring with a snubber ar- 40 `ranged as described. In` some trucks itmay be preferable to space one or both springs, with snubber or snubbersfunctioning as described, at proportionate distances between the axlesother than that shown.

. Other variations in detail may be made without departing from thegeneral arrangement, and the exclusive use of those modications comingwithin therscope of the claims is contemplated.

what is Yclaimed is: i v j 1. In a railway vehicle truck, twoy spacedwheeled axles, structure extending between said axles and supportedtherefrom, a truck frame including a wheel piece and yielding unitssupporting said wheel piece from said structure, one oi said units beingnearer to onevoi said axles than to the other axle and Ythe other `unitbeing approximately equi-distant from the axles, the inst-mentionedunitV comprising a substantially free acting spring, and theY other unitcomprising a spring having a snubber associated therewith butfunctioning only duringaction of the spring between approximately itsnormal full load height andritsl solid height. Y'

2. In a railway Vvehicle truck, three wheeled axles spaced apartlongitudinally'of the truck and provided with ljournal boxes andequalizers, each equalizer being supported at one end upon a, journalbox on one of the end axles andr at its other end upon a journalbox onthe middle'axle, a truck frame includinga wheel piece extending oversaid equalizer, and a series of yielding Vto the middle axle `.and beingfree actingr aty all Spring units Il and |72 form a. group, the Y Y Theabove description relatesto the preferredY 4. A truck construction asdescribed in claim 1 in which the snubber is complete independently ofthe springs and has operative engagement with its supporting equalizerandthe wheel piece yindependently of the springs,

whereby the "springs may be replaced without disassembling the snubber.

JAMES C. TRAVILLA, JR.

